The subject matter disclosed herein generally relates to electric machines. More specifically, the subject disclosure relates to phase lead connections for parallel path electric machines.
A stator of a typical electric machine includes a stator winding which is wound in series or wound with a defined number of parallel paths, and may also include more than one phase. The wiring harness which connects the electric machine to, for example, an inverter, typically provides one connector per phase, regardless of the number of parallel paths in the machine. Typically an eyelet is formed in each end of each phase lead to connect to the wiring harness. For example, in a machine with three phases (A, B, C) and two parallel paths (1,2), six eyelets (A1, A2, B1, B2, C1, C2) are formed. The eyelets include mating surfaces so that the eyelets for each phase may be placed in contact with each other at the mating surfaces, then secured together (A1 to A2, B1 to B2, C1 to C2). Each of the three pairs of eyelets is then connected to the wiring harness. This type of connection, however, has several concerns associated with it. First, the connection between the mating surfaces may be highly resistive due to oxidation on the mating surfaces. Second, improper forming and/or handling of the eyelets and the mating surfaces results in a low amount of surface area of contact between the two mating surfaces. This results in a failure of current transfer through the eyelets and overheating and failure of the phase leads. Third, the eyelets must be secured together and withstand vibration and other loads in the operating environment. If the connection between eyelets loosens or breaks, excessive heat is generated in the joint again resulting in failure of the phase leads.
The art would well receive an improved connection scheme through which operational efficiency of the electric machine can be improved.